This invention relates specifically to an endoscopic surgical stapler having a generally flat configuration with a low profile especially adapted for insertion through a trocar cannula during minimally invasive surgical procedures.
Endoscopic surgery has recently exploded on the surgical scene. Endoscopy represents a form of minimally invasive surgery where surgery is performed through small diameter openings made through the body wall providing access to the surgical site. These openings are now typically made with a trocar, which is a puncturing device for gaining such access. Once the cutting tip of the trocar has penetrated the body wall, the cutting implement is removed from the trocar, leaving behind the trocar cannula, which is a tubular sheath, for providing a pathway into the body for required endoscopic instrumentation and surgical instruments.
Endoscopic surgery represents a significant advance in the state of surgical practice because overall trauma to the patient is significantly decreased, healing times are shortened, and hospital costs are dramatically reduced. While the explosion in endoscopic surgical techniques continues, it has created an ever pressing need for surgical instruments to keep pace with the innovative procedural advances which minimally invasive surgery can bring.
Recent advances have been made in the design and operation of surgical staplers for their adaptation to endoscopic surgery. Surgical staplers fire staples to fasten bodily tissue during surgery, and have become a viable alternative to traditional suturing techniques for fastening because of the relative ease in which the staples can be placed. An example of an endoscopic stapler can be found in U.S. Pat. No. 5,170,925, which describes an endoscopic stapler for remotely laying two double parallel rows of staples. The ability to remotely fire the stapler to place the staples is critical for endoscopic applications, since it is necessary to fire the stapler through the small diameter trocar cannula, unlike open surgical procedures where the surgeon has direct access to the surgical site. The stapler described in this patent is housed within a tubular sheath configured to fit through the cannula of the surgical trocar, and the stapling functions can be accomplished remotely from the anvil and firing mechanisms. The rows of staples are placed along the longitudinal axis of the sheath, and a knife can be actuated to cut between the center two rows of staples. This type of stapler is now routinely used during endoscopic bowel surgery. Unfortunately, it is incapable of placing staples transversely to the longitudinal axis of its tubular sheath, which is an important consideration for certain surgical procedures.
The importance of being able to fire staples transversely to the longitudinal axis of the housing or shaft of the stapler should not be underestimated. The transverse placement of staples is important for numerous surgical techniques, especially for a procedure referred to as an "esophageal reflux procedure". Gastro-esophageal reflux, or "GER", can be a major problem with profound consequences for both children and adults. Symptoms of GER commonly include reflux or regurgitation of the stomach contents up into the esophagus. Although numerous "anti-reflux" procedures now are beginning to be developed, all of them require the use of surgical staples for fastening. In particular, an endoscopic surgical stapler would be particularly desired for this application, especially one which sequentially fires numerous staples, one staple at a time, in a direction which is transverse to the longitudinal axis of the stapler shaft. Ideally, this stapler would also have the ability to compress the tissue before the staples are fired.
Staplers currently do exist which fire staples transversely to the longitudinal axis of the stapler shaft or housing. See, for example, U.S. Pat. No. 5,161,725, which describes a rotating head skin stapler for approximating skin tissue. This stapler fires staples transversely relative to the longitudinal axis of the stapler housing and its rotating head. Unfortunately, the stapler housing has a very large profile, and therefore would not be conducive for endoscopic surgery because it would be impossible to insert the stapler through a small diameter endoscopic opening. In addition, it is incapable of compressing the tissue prior to firing. Another example of such a stapler is the Brookstone Staoler (marketed by Brookstone), which is a non-surgical stapler having a low, flat profile when the stapler is not being fired. Its flat profile can be obtained because the cartridge can be retracted from its staple-forming position. The staples are fired transversely relative to the longitudinal axis of the stapler shaft. Once again, however, this stapler is not adapted for endoscopic use because of the user's inability to actuate the driving and staple-forming mechanisms of the stapler from a position remote from these mechanisms themselves.
In view of the deficiencies inherent with the prior art staplers, what is needed is a multi-fire endoscopic stapler which has a flat, low profile to facilitate its use during minimally invasive endoscopic surgical procedures. Such a stapler would have the ability not only to fire staples transversely relative to the longitudinal axis of its shaft, but also compress tissue within its jaws prior to firing of the staples. The desired stapler would be capable of sequentially firing numerous staples, one staple at a time. In addition, it is critical for the proper operation of such an endoscopic stapler to have the ability to form each staple from a position remote from the staple-forming mechanism.